The JBL JRX218S 18" Compact Subwoofer is driven by an 18.0" (457.2mm) woofer with a cast frame and 3.0" (76.2mm) voice-coil.

Features:
Features a 350 W (continuous) and 1400 W (peak) power capacity.
The rugged enclosure is constructed from 0.75" (19mm) MDF (Medium Density Fiberboard) using advanced adhesives and mechanical fastener technology for durability and improved low-frequency performance. The enclosure is covered in black carpet.
A top mounted, cast aluminum 1.3" (35mm) pole mount receptacle can receive an optional SS3BK pole to facilitate use of the JRX218S as a base for a mid-high speaker cabinet.
Non-resonant, all-steel handles are used.
An 18-gauge perforated steel grille protects components from damage.

JBL JRX218S Specs:
Power Rating 350 / 1400 W
Frequency Range At -10 dB: 38 to 300 Hz
Frequency Response At ±3 dB: 55 to 300 Hz
Sensitivity 96 dB SPL (@1m)
Nominal Impedance 4Ω
Amplifier Power 350 to 700 W into 4Ω
Crossover Adjustment 30 Hz HPF, 24 dB / octave; 80 to 100 Hz LPF, 24 dB / octave
Maximum SPL 127 dB
Low Frequency Driver JBL 2043-G
Input Connectors 1 x Neutrik Speakon NL-4
1 x 0.25" (6.35 mm) TS phone jack; parallel
Dimensions (H x W x D) 23.5 x 20.3 x 22.0" (605.0 x 508.0 x 551.0 mm)
Weight 89.0 lb (40.4 kg)